Conventionally, in a known example of a circuit structure, a circuit board is overlaid on a heat release member releasing heat of the circuit board to an exterior. In a circuit structure of this type, a circuit board is bonded on top of a heat release member using an adhesive. In a circuit structure in Patent Literature 1, when a sheet body, in which insulation fibers are woven into a sheet, is overlaid on the adhesive applied to a top of the heat release member, the adhesive passes through the entire sheet body almost evenly. By adding the circuit over the sheet body and pressing the circuit toward the heat release member, the circuit is fixated to the top of the heat release member.